Tuning device for guitars



T. w. MITCHELL TUNING DEVICE FOR GUITARS Sept. 26, 1950 2 Sheets-Sheet 2 Filed Dec. so, 1948 Thomas M. Mitchell INVENTOR.

9 BY on! Patented Sept. 26, 1950 TUNING DEVICE FOR GUITARS Thomas W. Mitchell, St. Louis, Mo., assignor of forty-nine per cent to R. C. Marrs, St. Louis, Mo.

Application December 30, 1948, Serial No. 68,314

6 Claims. 1

The present invention relates to string fastening, tensioning and tuning devices used on I stringed musical instruments, and has more particular reference to a novel structural adaptation which is especially, but not necessarily, in-

tended to be used on guitars.

In the field of invention under advisement tensioning and tuning a string is ordinaril dependent upon rotary posts and turning and adjusting keys which are mounted on the head at the outer end of the neck just beyond the transverse nut. Various forms of devices are used at the opposite end of the body for securing the knotted, or equivalently constructed, end of the string. Since. the pitches of the strings are altered and become either sharp or flat while the instrument is being played, it is obviously inconvenient to accomplish quick tuning. Therefore,

it has been proposed to install the string ten-- sioning and tuning means at the butt or tailend vice which is such in construction that it aptly fulfills the requirements and offers reliable facilities whereby it will be possible for the guitarist to attain wanted ends with requisite satisfaction and precision.

In carrying out the principles of my invention, I provide easy-to-use means on the headed outer end of the neck to expedite the initial step of, securely anchoring the so-called knotted end ofa string, said means being effectively designed andfashioned to perform with requisite nicety.

In carrying out the principles of the tensioning and tuning means at the opposite or tail end of the body, I achieve what is wanted by providing a simple and practical clamp and associating therewith feasible and appropriately constructed plate means, which means is hinged for selflevelling on a part of the clamp and which provides a highly satisfactory adapter or mount for an assemblage of rotar slack take-up and tuning posts and individual manually manipulable adjusting shafts for the posts.

Further, in reducing to practice a preferred embodiment of the stated adapter means, I provide two .plates, one hinged to the tail clamp and the other hinged to the forward end of the first plate and overlying said plate and being separably connected to and functioning as a carrier for the posts and shafts in a manner to render the latter readily accessible for replacement and repairing and similar purposes.

A more specific objective is to provide a novel rotatable string anchoring post characterized by a shank and a head centrall slitted, the head being circular and marginally grooved, whereby to provide a novel post insuring absolutely reliable retention of the string, once it is attached to said post.

A still further achievementhas to do with the adoption and use of actuating shafts for the tuning posts, which shafts have optionally usable knob-like grips at their outer ends and knurled or milled rollers intermediate their ends, thus insuring that quick tuning is not only possible but may be had by the touch of a finger.

. Other objects and advantages will become more readily apparent from the following descriptionand the accompanying illustrative drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the views:

Figure 1 is a top plan view of a conventionaltype guitar equipped with my novel string fastening and tuning devices.

Figure 2 is an enlarged fragmentaryplan view of the headed end of the neck detailing the relatively fixed string anchoring bar.

Figure 3 is a section on the line 3-3 of Figure v 2, looking in the direction of the arrows.

Figure 4 is an enlarged fragmentary top plan showing the tail end of the guitar body and showing, in elevationand section, my novel string fastening, tensioning and tuning devices.

Figure 5 is a side or edge elevation of the stated devices. v

Figure 6 is a cross-section on the line 6--6 of Figure 5, looking in the direction of the arrows. Figure 7 is an enlarged detail perspective of one of the tuning posts by itself. Referring now to the drawings by distinguishing reference numerals and lead lines, the guitar, which is a conventional type, is characterized by the usual hollow body 9 and includes a rim I0 (see Fig. 5), a bottom or back H and top 12. The rearward or tail end of the body is denoted by the numeral 13 and the forward end by the numeral M. Attached to and projecting from the forward end, as customary, is a neck 15 provided with a fretted finger-board I6 terminating at the outer end in a head I! with or without an ornamental scroll [8. As better shown in Figures 2 and 3 the numeral [9 designates a cross member commonly referred to as a nut and notched in the usual way to assist in fastening the strings against displacement. The strings at this end are provided with anchoring knots 0r suitable retentive tip elements 2| and in the present instance they are removably anchored on the relatively fixed anchoring bar unit 22. This comprises a rigid bar 23 which abuts the nut I9 and which has keeper seats or crotches 24' for the string-ends. Projecting outwardly and at right angles from the bar are spear-shaped guide and piloting fingers 25 which are of suitable contours to facilitate the step of feeding a given string into its seating or keeper crotch 24. Usually, this general type of an anchoring bar is at the tail-end of the body as is well known. In the instant situation it is on the headed end of the neck. Incidentally, the numerals 26 designate tone holes in the top and the numeral 2? denotes a bridge.

Reference is had now to Figure 5, wherein the tail clamp is denoted, as a unitary assemblage, by the numeral 28. An angle clip or clamp 29 is provided at the bottom and has an appropriate protective pad 30. A similar angle clamp 3i is provided at the top and has a protective pad 32. The clamps are connected together and fastened in place by turnbuckles 33. The clamp 3i is provided with an upstanding fiange 34 and this fiange has an appropriate hinged knuckle 35 as better shown in Figure 4. In practice I provide a pair of the stated clamps 28 and they are situated at the approximate positions shown. It is believed that the clamps may be collectively referred to either in a singular sense as clamp means or simply a clamp.

The adapter means, as an assembly, is denoted by the numeral 35 and is hingedly connected to the clamp means and is self-levelling. The means is preferably made up of a bottom plate 37 of general wedge-shaped configuration, said plate being fiat and having hinge knuckles 38 at its outer end embracing a hinge pintle 39 also embraced by the knuckles 35. Thus, the pin and knuckle means provide satisfactory hinging anchorage of the plate 31 on the clamp means.

I'here is a similar arrangement of hinge means at the forward or inner end of the plate 31. That is to say, the plate 31 has hinge knuckles 39 which coact with complemental hinge knuckles 40 on the upper or top plate 4|. The several knuckles are joined together by a hinge pintle or pin 42. The outer end of the plate 4| has a depending apron 43 with a lip or flange 44 removably secured to the intermediate part of the plate 37 by screws or similar fastenings 45 as shown in Figure 4.

I Figure I and each post is denoted, as a unitary device, by the numeral 46. It comprises a shank 47 with a disk-like string wrapping and slack take-up head 48. The shank and head are axially slitted to provide kerf means 49 for the free bendable end of the coacting string. This slitted construction makes the head sufficiently yieldable that when the string is coiled or wrapped in the peripheral groove 50 in the head, it is effectively gripped and slippage is virtually eliminated. Thus, the post is not only for tensioning but for secure anchorage as well. Each tuning post, that is the shank portion, is provided with a worm wheel 5| as detailed in Figure 6.

I now call attention to the adjusting rods or shafts 52. Each is the same in construction and the description of one will suffice fo all. The

. left hand end of the shaft, as shown in Figure 5,

is fastened and journalled for rotation in a bearing block or lug 53 on the underside of the plate 4|. The intermediate portion of the shaft is journalled in a bearing provided therefor as at 54 in the apron 43. A worm-screw 55 on the shaft is meshed with the coacting worm wheel by the usual type of connection between post and shaft. The outer end of each shaft is provided with a finger-gripping knob 56 and in practice the knobs will vary in size and shape for convenience of use. On the intermediate portion of the shaft is keyed a horizontal knurled or milled roller 51 and this operates in slots provided there for in the respective plates 31 and 4|. In tuning, the user may employ either the knob 56 or the roller 5? or both. Major tuning results may perhaps best be accomplished by using the knob 56 and a slight adjustment, for either fiatting or sharping a string, may be attained through the use of the rollers 51.

It follows that I provide two clamps constituting novel clamp means on the tail end of the body with the upper clamps serving for satisfactory anchoring and hinging of the plate 31 of the adapter means 3-6. The means 36, as a unit, floats to accommodate the necessary level of the string. Thus, said means is substantially self-levelling.

It is believed that the manner of attaching the string-ends to the posts is clear and that the manner in which the tuning posts are rotated for increa ing and decreasing tension on strings is perfectly clear. It follows that a construction made in accordance with that herein shown and described fulfills the requirements of the objectives mentioned in the introductory portion of this specification.

It is evident, fo instance, that a single plate may be provided to carry the post and to provide the hinging effect. However, the double plate arrangement is generallv preferred as a top plate is inde endently hinged and eparablv connected with the lower plate so as to permit the same to be swung up to expose the mechanism on the underside to facilitate making adjustments and repairs.

Changes in sha e, size, materials and rearrangement of details and parts may be resorted to in actual practice, so long as they do not depart from the spirit of the invent on or the scope of the appended claims, as is well understood.

Having described the invention, what is claimed as new is:

1. A string fastenin tensioning and tuning attachment for the tail end of a guitar body comprising a clamp, plate means hingedly connected with said clamp, tuning posts mounted for rotation on said plate means, individual shafts also mounted for rotation on said plate means at right an les to said posts, and operating connections between the shafts and posts.

2. A string fastenin tension ng and tuning attachment for the tail end of a guitar body comprising a clamp. plate means hingedly connected with said clamp, tuning posts mounted for rotation on said plate means. individual shafts also mounted for rotation on said plate means at right angles to said posts. and operating connections between the shafts and posts, embodying worm wheels and worm-screws operatively geared to the worm wheels.

3. A string fastening, tensioning and tuning I attachment for the tail end of a guitar body comprising a clamp, plate means hingedly connected with said clamp, tuning posts mounted for rotaroller intermediate its ends.

4. A string fastening, tensioning and tuning V attachment for the tail end of a guitar body comprising a clamp, a plate hingedly connected at one end portion to said clamp, a complemental plate hingedly connected to the opposite end portion of said first named plate and overlying and separably fastened on the latter, tuning posts operatively and rotatably mounted on said second plate, individual selectively manipulable shafts mounted for use on said second plate and operably connected with said posts.

5. A string fastening, tensioning and tuning attachment for the tail end of a guitar body comprising a clamp, a plate hingedly connected at one end portion to said clamp, a complemental plate hingedly connected to the opposite end portion of said first named plate and overlying and separably fastened on the latter, tuning posts operatively and rotatably mounted on said second plate, individual selectively manipulable shafts mounted for use on said second @plate and operably connected with said posts, each shaft having a finger-gripping knob at its outer end and a knurled roller intermediate its ends.

6. A guitar comprising a body provided with a fretted neck and head at the outer end of said neck, a tail clamp embodying top and bottom clamping units connected together by turnbuckles and removably clamped on the tail end of said body, said top unit having an upstanding flange, adapter means overlying the top of said body and hingedly attached to said upstanding flange, and a plurality of split string tensioning and tuning posts mounted for operation on said adapter means.

THOMAS W. MITCHELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 487,879 Middlebrook Dec. 13, 1892 2,029,134 Stanley et a1. Jan. 28, 1936 2,097,103 Pitsenborger Oct. 26, 1937 2,196,817 Sottnek Apr. 9, 1940 2,216,601 Nelson Oct. 1, 1940 FOREIGN PATENTS Number Country Date 431,149 Germany July 3, 1926 

